HEIDENHAIN TNC 640, User Manual, Page: 294 / 948

Programming Contours | Approaching and departing a contour
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HEIDENHAIN | TNC 640 | Conversational Programming User's Manual | 10/2017
Approaching on a circular path with tangential
connection:
APPR CT
The tool moves on a straight line from the starting point P
S
to an
auxiliary point P
H
. It then moves from PH to the first contour point
PA following a circular arc that is tangential to the first contour
element.
The arc from P
H
to P
A
is determined through the radius R and
the center angle
CCA
. The direction of rotation of the circular arc
is automatically derived from the tool path for the first contour
element.
Use any path function to approach the starting point P
S
.
Initiate the dialog with the
APPR DEP
key and
APPR CT
soft
key
Coordinates of the first contour point P
A
Radius R of the circular arc
If the tool should approach the workpiece
in the direction defined by the radius
compensation: Enter R as a positive value
If the tool should approach the workpiece
opposite to the radius compensation: Enter R
as a negative value.
Center angle
CCA
of the arc
CCA can be entered only as a positive value.
Maximum input value 360°
Radius compensation
RR/RL
for machining
Example
7 L X+40 Y+10 R0 FMAX M3
Approach PS without radius compensation
8 APPR CT X+10 Y+20 Z-10 CCA180 R+10 RR F100
PA with radius compensation RR, radius R=10
9 L X+20 Y+35
End point of the first contour element
10 L ...
Next contour element